This invention relates to inboard-outboard (I/O) marine drive units for boats wherein an inboard engine has a rearwardly extending drive shaft coupled through universal joints to power transmission means in an outboard power leg having an upper gear housing and a propeller carried at the lower end of the power leg. The outboard power leg is carried aft of the stern and is mounted for pivoting on two mutually and generally perpendicular axes. It is therefore free to swing laterally for steering the boat while also being free to swing vertically such that the lower end thereof may move rearwardly and upwardly in a tilting, trimming and/or kick-up motion.
In certain instances it has been found desirable to mount the power leg relative to the transom such that the forward portion of the upper gear housing extends slightly into the transom opening. In such an arrangement the lateral turning of the power leg and its vertical swinging on kick-up require a relatively large transom opening in order to avoid contact between the power leg upper gear housing and the inner peripheral edges of the transom opening. At times, kick-up movement can be quite violent and potentially harmful if contact occurs between the unit and transom.
However, the use of a slightly large transom opening is in some cases unsightly and has been found in some cases to prohibit the use of the aforementioned inboard marine mounting arrangement on boats having small transoms.